Latching mechanism for magnetically actuated micro-electro-mechanical devices

Abstract

A latching mechanism is provided for selectively latching mirrors in an optical switch. The mirrors are selectively movable between rest and actuated positions. The latching mechanism provides stable latching of mirrors in an actuated position, i.e., without power being applied to maintain the actuated state.

1. An optical switch mirror array comprising a plurality of mirror assemblies, each mirror assembly including:
 a mirror selectively movable between rest and actuated positions; and 
 a latching mechanism detachably securing said mirror in said actuated position without consuming power, 
 wherein each mirror assembly further comprises a support on which said mirror is movably mounted, and wherein said latching mechanism includes magnetic material on said mirror and said support, and 
 wherein said magnetic material is a hard magnetic material that has been permanently magnetized. 
 
   
   
     2. The optical switch mirror array of  claim 1  wherein said latching mechanism includes magnetic elements that are engageable to detachably secure said mirror. 
   
   
     3. The optical switch mirror array of  claim 1  further comprising a magnetic field source for inducing magnetism to detachably secure said mirror. 
   
   
     4. The optical switch mirror array of  claim 1  wherein said mirror is a thin planar element having a reflective side, and wherein said magnetic material on said mirror is on a side of said mirror opposite said reflective side. 
   
   
     5. The optical switch mirror array of  claim 1  wherein said mirror includes a reflective side, and wherein said magnetic material on said mirror is on said reflective side. 
   
   
     6. The optical switch mirror array of  claim 1  wherein said magnetic material on said mirror comprises a thin film applied to said mirror. 
   
   
     7. The optical switch mirror array of  claim 6  wherein said thin film forms a reflective surface of said mirror. 
   
   
     8. The optical switch mirror array of  claim 6  wherein said thin film comprises a thin film sandwich of Ti/M/Au, where M represents Ni, Fe, or Co, or alloys containing Ni, Fe, or Co. 
   
   
     9. The optical switch mirror array of  claim 1  wherein said magnetic material comprises a material selected from the group consisting of Ni, Fe, Co, and alloys containing Ni, Fe or Co. 
   
   
     10. The optical switch mirror array of  claim 1  wherein each of said mirrors is movably supported on a support structure, and said support structure includes a stop to inhibit movement of said mirror beyond said actuated position. 
   
   
     11. The optical switch mirror array of  claim 1  wherein each of said mirrors is hinged to rotate about 90 degrees when moved between said rest and actuated positions. 
   
   
     12. The optical switch mirror array of  claim 1  wherein said latching mechanism releases said mirror when a current pulse is applied to an actuation coil at said mirror. 
   
   
     13. A latch for a reflector in an optical switch, said reflector being movably mounted on a support structure and selectively movable between rest and actuated positions, said latch including a first element on said reflector and a second element on said support structure, said elements cooperating to releasably secure said reflector in said actuated position by permanent magnetism, wherein said elements comprise a hard magnetic material that has been permanently magnetized. 
   
   
     14. The latch of  claim 13  wherein said reflector includes a reflective side, and wherein said magnetic material on said reflector is on a side of said reflector opposite said reflective side. 
   
   
     15. The latch of  claim 13  wherein said reflector includes a reflective side, and wherein said magnetic material on said reflector is on said reflective side. 
   
   
     16. The latch of  claim 13  wherein said magnetic material on said reflector comprises a thin film applied to said reflector. 
   
   
     17. The latch of  claim 16  wherein said thin film forms a reflective surface of said reflector. 
   
   
     18. The latch of  claim 16  wherein said thin film comprises a thin film sandwich of Ti/M/Au, where M represents Ni, Fe, or Co, or alloys containing Ni, Fe, or Co. 
   
   
     19. The latch of  claim 13  wherein said magnetic material comprises a material selected from the group consisting of Ni, Fe, Co, and alloys containing Ni, Fe or Co. 
   
   
     20. The latch of  claim 13  wherein said support structure includes a stop to inhibit movement of said reflector beyond said actuated position. 
   
   
     21. The latch of  claim 13  wherein said reflector is hinged on said support structure to rotate about 90 degrees when moved between said rest and actuated positions. 
   
   
     22. The latch of  claim 13  wherein said latch releases said reflector when a current pulse is applied to an actuation coil at said reflector. 
   
   
     23. A mechanism for positioning a plurality of mirrors in an optical switch, said mirrors being individually addressable and movable between rest and actuated positions, said mechanism comprising:
 means for selectively moving mirrors between rest and actuated positions; and 
 a latch for providing stable latching of mirrors in an actuated position without consuming power, 
 wherein each of said mirrors is movably supported on a support structure, and 
 wherein said latch comprises magnetic material on said mirror and on said support structure, and 
 wherein said magnetic material is a hard magnetic material that has been permanently magnetized. 
 
   
   
     24. The mechanism of  claim 23  wherein said latch includes means for applying magnetic force to releasably secure said mirrors in said actuated position. 
   
   
     25. The mechanism of  claim 23  wherein said latch comprises magnetically engageable elements. 
   
   
     26. The mechanism of  claim 23  wherein each said mirror includes a reflective side, and wherein said magnetic material on said mirror is on a side of said mirror opposite said reflective side. 
   
   
     27. The mechanism of  claim 23  wherein each of said mirrors includes a reflective side, and wherein said magnetic material on said mirror is on said reflective side. 
   
   
     28. The mechanism of  claim 23  wherein said magnetic material on each said mirror comprises a thin film applied to said mirror. 
   
   
     29. The mechanism of  claim 28  wherein said thin film forms a reflective surface of said mirror. 
   
   
     30. The mechanism of  claim 28  wherein said thin film comprises a thin film sandwich of Ti/M/Au, where M represents Ni, Fe, or Co, or alloys containing Ni, Fe, or Co. 
   
   
     31. The mechanism of  claim 23  wherein said magnetic material comprises a material selected from the group consisting of Ni, Fe, Co, and alloys containing Ni, Fe or Co. 
   
   
     32. The mechanism of  claim 23  wherein each said mirror is movably supported on a support structure, and said support structure includes a stop to inhibit movement of said mirror beyond said actuated position. 
   
   
     33. The mechanism of  claim 23  wherein each said mirror is rotated about 90 degrees when moved between said rest and actuated positions. 
   
   
     34. The mechanism of  claim 23  wherein said latch releases one of said mirrors when a current pulse is applied to an actuation coil at said one of said mirrors. 
   
   
     35. A magnetically actuated mirror array apparatus for an optical switch, comprising:
 (a) an array of magnetically actuated mirror elements, each element including:
 a mirror; 
 an actuation coil on said mirror; 
 a support structure movably supporting said mirror, said mirror selectively movable between rest and actuated positions; and 
 a latch for releasably securing said mirror in said actuated position without consuming power, wherein said latch comprises magnetic materials on each said mirror and support structure supporting said mirror, and wherein said magnetic materials comprise a hard magnetic material that has been permanently magnetized; and 
 
 (b) an array of magnets proximate said mirror elements. 
 
   
   
     36. An optical switch comprising:
 (a) an array of magnetically actuated mirror devices, each device comprising:
 a mirror; 
 a support structure for movably supporting said mirror; 
 an actuation coil on said mirror for causing movement of said mirror between rest and actuated positions; and 
 means for providing stable latching of said mirror in said actuated position without consuming power, wherein said means for providing stable latching comprise magnetic materials on each said mirror and support structure supporting said mirror, and wherein said magnetic materials are hard magnetic materials that have been permanently magnetized; and 
 
 (b) an array of magnets proximate said array of magnetically actuated mirror devices. 
 
   
   
     37. The optical switch of  claim 36  wherein said means for providing stable latching release said mirror when a current pulse is applied to said actuation coil. 
   
   
     38. An apparatus for positioning mirrors in an array of mirrors forming an optical switch, comprising:
 means for moving a selected mirror from a rest to an actuated position; and 
 means for releasably securing said mirror in said actuated position without consuming power, wherein said means for releasably securing said mirror include a magnetic latch comprising hard magnetic materials that have been permanently magnetized.